CN111875778B

CN111875778B - Method for preparing epoxy resin from triglycidyl isocyanurate production by-product

Info

Publication number: CN111875778B
Application number: CN202010753111.5A
Authority: CN
Inventors: 徐林; 邓生财; 黄杰军; 丁克鸿; 张寅�; 马庆炎; 胡金良
Original assignee: Jiangsu Ruixiang Chemical Co Ltd; Jiangsu Yangnong Chemical Group Co Ltd
Current assignee: Jiangsu Ruixiang Chemical Co Ltd; Jiangsu Yangnong Chemical Group Co Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2022-12-09
Anticipated expiration: 2040-07-30
Also published as: CN111875778A

Abstract

The invention provides a method for preparing epoxy resin from triglycidyl isocyanurate production byproducts, which is characterized in that the triglycidyl isocyanurate production byproducts, epichlorohydrin and bisphenol A are subjected to ring-opening polycondensation and then are subjected to ring-closing to form solid epoxy resin, so that the triglycidyl isocyanurate production byproducts can be recycled, the environmental pressure is relieved, the TGIC production cost is greatly reduced, and the prepared solid epoxy resin has excellent performance and meets the market demand.

Description

Method for preparing epoxy resin from triglycidyl isocyanurate production by-product

Technical Field

The invention relates to the technical field of waste treatment, in particular to a method for preparing epoxy resin from triglycidyl isocyanurate production byproducts.

Background

Epoxy resin is a general high molecular organic compound containing two or more than two epoxy groups, can form an insoluble three-dimensional reticular polymer by cross-linking reaction with various curing agents, and the cured epoxy resin has excellent mechanical property, adhesive property, electrical insulating property and chemical resistance, so the epoxy resin has common application in the industries of coatings, foods, chemical industry and anticorrosion, and the main production steps comprise: bisphenol A and epichlorohydrin generate crude epoxy resin under the action of sodium hydroxide, and the crude epoxy resin is washed and refined to obtain commercial epoxy resin, wherein the specific reaction formula is as follows:

triglycidyl isocyanurate (1, 3,5-triglycidyl isocyanurate, TGIC) is used as a functional epoxy compound which is matched with carboxyl-containing polyester resin for use, is a polyepoxy triazine heterocyclic ring-containing compound, has three epoxy functional groups and is high in reactivity. Compared with the traditional linear bisphenol A epoxy resin, the epoxy resin is different in that the epoxy resin does not contain benzene rings and ether bonds, so that a cured coating film has excellent ultraviolet resistance and heat resistance, is mainly used for preparing powder coating with excellent weather resistance, and has the outstanding advantages of light retention, color retention, chalking resistance, heat resistance and excellent adhesive force performance to metal substrates, so that the epoxy resin occupies a large powder coating market at home and abroad.

TGIC is prepared by the ring-closure reaction of Epichlorohydrin (ECH) and cyanuric acid under the alkaline condition after the reaction, the product is desalted, the excessive ECH is distilled to obtain an initial product, the final product can be obtained after the recrystallization treatment of methanol and the centrifugation and drying, and the main by-product is in the recrystallization mother liquor generated in the recrystallization treatment of methanol.

Wherein, the main products in the TGIC synthesis process are shown as the following formula:

the TGIC methanol recrystallization mother liquor byproduct contains 20-30 wt% of methanol, and the main components of the rest substances are TGIC which is not completely crystallized and separated, a byproduct which does not have a ring closure reaction under an alkaline condition and contains two epoxy groups and one epoxy group, a part of TGIC polymer which generates epoxy ring-opening polymerization in the production process, and the like, wherein the amount of the byproduct is about 2 ten thousand tons according to the annual output of the TGIC in China at present. At present, the by-product is not reasonably utilized, and domestic TGIC manufacturers generally treat the by-product as waste, so that resource waste and environmental pollution are caused.

Therefore, there is a need to develop a method for recycling TGIC methanol recrystallization mother liquor by-products, which can alleviate the environmental protection pressure and improve the economic value.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for preparing epoxy resin from TGIC production byproducts, which utilizes the ring-opening polycondensation and the ring-closing cyclization of isocyanuric acid mono-condensation, di-condensation and triglycidyl ester in the triglycidyl isocyanurate production byproducts, epichlorohydrin and bisphenol A to form solid epoxy resin, so that the method not only can utilize the resources of the triglycidyl isocyanurate production byproducts, relieve the environmental pressure and greatly reduce the TGIC production cost, but also can prepare the solid epoxy resin with excellent performance and meet the market demand.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for preparing an epoxy resin from a triglycidyl isocyanurate production byproduct, comprising: the epoxy resin is prepared from the byproducts of triglycidyl isocyanurate production, bisphenol A and epichlorohydrin under the action of alkali.

Aiming at the problem that TGIC production cost is high because the existing TGIC production by-product is directly treated as waste, the method for preparing the epoxy resin from the triglycidyl isocyanurate production by-product is used for preparing the epoxy resin with bisphenol A and epoxy chloropropane under the action of alkali, so that resource utilization of the TGIC production by-product is well realized, components in the TGIC production by-product can better participate in a reaction to be converted into the epoxy resin, the TGIC production cost is reduced, the environmental pressure is relieved, meanwhile, the TGIC production by-product has a modification effect on the epoxy resin, and the prepared epoxy resin has excellent performance and higher industrial application value.

Preferably, the triglycidyl isocyanurate production by-product comprises triglycidyl isocyanurate.

The TGIC production byproduct contains triglycidyl isocyanurate, and the ultraviolet resistance and heat resistance of the epoxy resin can be improved by the triglycidyl isocyanurate participating in the preparation of the epoxy resin.

Preferably, the triglycidyl isocyanurate production by-product further comprises any one or a combination of at least two of 2, 3-substituted ring-closed epoxypropyl isocyanurate, monoglycidyl isocyanurate, diglycidyl isocyanurate, or 1-chloro-2-hydroxy-propyl isocyanurate, with typical non-limiting combinations being the combination of monoglycidyl isocyanurate and diglycidyl isocyanurate, monoglycidyl isocyanurate and 1-chloro-2-hydroxy-propyl isocyanurate, diglycidyl isocyanurate and 1-chloro-2-hydroxy-propyl isocyanurate, and the like.

The byproduct of TGIC production also contains 2,3 substituted closed-loop epoxypropyl isocyanurate and other substances, and the substances can be subjected to ring-opening polycondensation with epoxy chloropropane and bisphenol A and then closed-loop to form solid epoxy resin in the reaction process, so that the byproducts generated in the TGIC preparation process are fully used, the byproducts can be recycled at one time without a complex separation process, and the TGIC production cost is greatly reduced.

Preferably, the epoxy value of the triglycidyl isocyanurate production by-product is 0.3 to 0.5moL epoxy group/100 g, and may be, for example, 0.3moL epoxy group/100 g, 0.32moL epoxy group/100 g, 0.34moL epoxy group/100 g, 0.35moL epoxy group/100 g, 0.38moL epoxy group/100 g, 0.4moL epoxy group/100 g, 0.42moL epoxy group/100 g, 0.45moL epoxy group/100 g, 0.48moL epoxy group/100 g, or 0.5moL epoxy group/100 g.

Preferably, the by-product in the production of triglycidyl isocyanurate is the residue of a liquid phase distillation still or distillation still after methanol recrystallization of triglycidyl isocyanurate.

The process for the production of TGIC production by-products of the present invention comprises: raw materials of Epichlorohydrin (ECH), cyanuric Acid (CA) and a proper amount of alkali are added into a synthesis kettle according to a certain proportion, a jacket is filled with steam and heated to 80 ℃, the synthesis reaction is carried out under normal pressure, an intermediate product of 1,3,5-tri (1' -chloro-2-hydroxy-propyl) isocyanurate is obtained, then the intermediate product and solid alkali (99wt NaOH) are added into a cyclization kettle, the cyclization reaction is carried out at the temperature of-5 ℃, a mixture containing TGIC is obtained, the mixture enters a filter-press tank for filtration, and the solid phase is solid salt containing the epichlorohydrin. And (3) standing and layering the liquid phase delayer, conveying the upper-layer water phase to an epoxy resin synthesis section for recycling, conveying the lower-layer organic phase to a distillation kettle, introducing 95 ℃ hot water into a jacket, reducing the pressure to-0.025 MPa for distillation, and recycling epoxy chloropropane to return the synthesis kettle for use. Adding methanol into the distilled solid material, recrystallizing with a crystallization kettle to obtain TGIC, separating with a centrifuge, and drying the separated solid TGIC to remove methanol to obtain solid TGIC. Transferring the separated liquid phase to a rectifying still, introducing hot water of 80 ℃ into a jacket, rectifying at normal pressure, returning the rectified methanol solvent to the crystallizing still for reuse, and obtaining the rest of the rectifying still as a TGIC production byproduct.

Preferably, the molar ratio of the epoxy value to the bisphenol a is 0.01 to 0.2, and can be, for example, 0.01.

Preferably, the molar ratio of the base to the bisphenol a is 1.7 to 4.5, and may be, for example, 1.7.

Preferably, the method comprises the steps of:

(1') carrying out a ring-opening reaction on a triglycidyl isocyanurate production byproduct, bisphenol and epichlorohydrin under the action of a first batch of alkali to obtain a pre-polymerization solution;

(2 ') carrying out a ring-closing reaction on the pre-polymerization solution obtained in the step (1') under the action of a solvent and a second batch of alkali to prepare epoxy resin and obtain a mixed product containing the epoxy resin;

(3 ') carrying out post-treatment on the mixed product obtained in the step (2') to obtain the solid epoxy resin.

Preferably, the method comprises the steps of:

(1) Carrying out ring-opening reaction on a triglycidyl isocyanurate production byproduct and bisphenol under the action of a first batch of alkali to obtain a pre-polymerization solution;

(2) Carrying out a ring-closing reaction on the pre-polymerization solution, bisphenol A and epoxy chloropropane in the step (1) under the action of a second batch of alkali to prepare epoxy resin and obtain a mixed product containing the epoxy resin;

(3) And (3) carrying out post-treatment on the mixed product obtained in the step (2) to obtain the solid epoxy resin.

According to the invention, bisphenol A is preferably added in two steps, firstly, a proper amount of bisphenol A reacts with the by-product in triglycidyl isocyanurate production to realize ring-opening reaction, and then the ring-opening reaction is carried out with epichlorohydrin, so that the softening point of the epoxy resin can be improved, and the obtained epoxy resin has better performance.

Preferably, the triglycidyl isocyanurate production by-product in the step (1) has an epoxy value to bisphenol A molar ratio of 0.5-1.

Preferably, the ring-opening reaction temperature is 75-85 ℃, for example, can be 75 degrees, 76 degrees, 77 degrees, 78 degrees, 79 degrees, 80 degrees, 81 degrees, 82 degrees, 83 degrees, 84 degrees or 85 degrees.

Preferably, the molar ratio of the first base to bisphenol a is 1.5 to 2.5, and can be, for example, 1.5.

Preferably, the first base comprises sodium hydroxide.

Preferably, the first base is sodium hydroxide solution.

Preferably, the sodium hydroxide solution has a mass concentration of 35 to 50wt%, and may be, for example, 35wt%, 36wt%, 38wt%, 40wt%, 42wt%, 45wt%, 50wt%, or the like.

Preferably, the sodium hydroxide solution is added dropwise.

Preferably, the dropping time is 10 to 20min, for example, 10min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min or 20min.

Preferably, the molar ratio of the bisphenol a in the step (2) to the bisphenol a in the step (1) is 10 to 16, and for example, 10.

Preferably, the molar ratio of the sum of the aromatic hydroxyl groups contained in the prepolymer liquid and the hydroxyl groups in the bisphenol a to epichlorohydrin is from 0.8 to 1, and can be, for example, from 0.8.

Preferably, the molar ratio of the second base to epichlorohydrin is 0.2 to 2, and can be, for example, 0.2.

Preferably, the second base comprises sodium hydroxide.

Preferably, the second base is a sodium hydroxide solution.

Preferably, the sodium hydroxide solution is added dropwise.

Preferably, a first solvent is also added to the ring closure reaction.

Preferably, the first solvent comprises water and an organic solvent.

Preferably, the organic solvent comprises any one or a combination of at least two of benzene, toluene, xylene, ortho-dichlorobenzene, or meta-dichlorobenzene, with typical non-limiting combinations being combinations of benzene and toluene, benzene and xylene, toluene and ortho-dichlorobenzene, xylene and ortho-dichlorobenzene, ortho-dichlorobenzene and meta-dichlorobenzene, meta-dichlorobenzene and benzene, and the like.

Preferably, the molar ratio of the organic solvent in the first solvent to the bisphenol a in step (2) is 0.5 to 1.1, and for example, can be 0.5.

Preferably, in the ring-closing reaction, bisphenol A, epichlorohydrin, water and an organic solvent are sequentially added into the pre-polymerization solution, and then a second batch of alkali is dropwise added.

Preferably, bisphenol A, epichlorohydrin, water and an organic solvent are sequentially added into the pre-polymerization solution at the temperature of 80-95 ℃, and then a second batch of alkali is dropwise added.

Preferably, the temperature of the ring-closure reaction in step (2) is 80 to 95 ℃, and may be, for example, 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 88 ℃, 90 ℃, 92 ℃ or 95 ℃.

Preferably, the ring closure reaction time is 2 to 4 hours, for example, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.3 hours, 3.5 hours, 3.8 hours, 4 hours, etc.

Preferably, the ring closure reaction is carried out under stirring conditions.

Preferably, the post-processing in step (3) comprises: and diluting the mixed product by using a second solvent, and sequentially carrying out solid-liquid separation, washing, solvent removal and cooling to obtain the solid epoxy resin.

Preferably, the second solvent comprises any one or a combination of at least two of benzene, toluene, xylene, ortho-dichlorobenzene, or meta-dichlorobenzene, with typical non-limiting combinations being combinations of benzene and toluene, benzene and xylene, toluene and ortho-dichlorobenzene, xylene and ortho-dichlorobenzene, ortho-dichlorobenzene and meta-dichlorobenzene, meta-dichlorobenzene and benzene, and the like.

Preferably, the means for removing the solvent comprises distillation.

The solid-liquid separation, washing and cooling methods are not particularly limited, and the steps or methods which can realize the above operations and are conventionally adopted by those skilled in the art can be adopted, or the methods can be appropriately adjusted according to actual conditions in the conventional methods, and thus, the methods are not particularly limited.

As a preferred technical scheme of the invention, the method comprises the following steps:

(1) Mixing a triglycidyl isocyanurate production byproduct with bisphenol A, dripping 35-50 wt% of sodium hydroxide solution within 10-20 min at 75-85 ℃, and carrying out ring-opening reaction to obtain a pre-polymerization solution;

wherein the triglycidyl isocyanurate production byproduct comprises triglycidyl isocyanurate;

the molar ratio of the epoxy value to the bisphenol A of the triglycidyl isocyanurate production by-product is (0.5-1);

(2) Sequentially adding bisphenol A, epoxy chloropropane, water and an organic solvent into the pre-polymerization solution in the step (1) at the temperature of 80-95 ℃, dropwise adding a sodium hydroxide solution with the mass concentration of 35-50 wt%, and maintaining the temperature of 80-95 ℃ to carry out a ring-closing reaction for 2-4 h to prepare epoxy resin, thereby obtaining a mixed product containing the epoxy resin;

wherein the molar ratio of the bisphenol A in the step (2) to the bisphenol A in the step (1) is 10-16;

the molar ratio of the sum of aromatic hydroxyl contained in the pre-polymerization liquid and hydroxyl in the bisphenol A to the epichlorohydrin is 0.8-1;

the molar ratio of the organic solvent to the bisphenol A in the step (2) is 0.5-1.1;

the molar ratio of sodium hydroxide to epichlorohydrin in the sodium hydroxide solution is 0.2-2;

(3) And (3) diluting the mixed product obtained in the step (2) by using a second solvent, and then sequentially carrying out solid-liquid separation, washing, solvent removal and cooling to obtain the solid epoxy resin.

The molecular structure of the TGIC production by-product and bisphenol A prepolymer in step (1) of the present invention is schematically illustrated by the following formula:

in a second aspect, the present invention provides an epoxy resin prepared by the method for preparing an epoxy resin from a by-product of triglycidyl isocyanurate production according to the first aspect.

The epoxy resin provided by the second aspect of the invention has excellent performance, low production cost and good market application value.

The molecular structure of epoxy resin in the prior art is as follows:

the epoxy resin prepared by the byproducts in the production of triglycidyl isocyanurate has the following structure:

from the molecular structure, the method for preparing the epoxy resin from the triglycidyl isocyanurate production byproduct has a modification effect on the structure of the epoxy resin, and n in the molecular structure represents the number of repeating units and is a natural number.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) The method for preparing the epoxy resin from the triglycidyl isocyanurate production byproduct realizes resource utilization of the TGIC production byproduct, and reduces the production cost of TGIC;

(2) According to the method for preparing the epoxy resin from the triglycidyl isocyanurate production byproduct, the TGIC production byproduct is converted into the epoxy resin, the yield is more than 92wt%, the chlorine content is less than or equal to 0.15wt%, and the chlorine content is less than or equal to 0.08wt% under the optimal condition, so that the environmental pressure is relieved, and the method has high environmental protection value;

(3) The method for preparing the epoxy resin from the triglycidyl isocyanurate production byproducts modifies the conventional epoxy resin through the TGIC production byproducts, the epoxy resin has a high softening point which is not less than 65 ℃, and the epoxy resin has a softening point which is not less than 75 ℃ under the optimal condition, has excellent performance, and can better meet the market demand.

Detailed Description

The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

1. Examples of the embodiments

Example 1

In this embodiment, the source of the by-product in triglycidyl isocyanurate production is the residue of the distillation of TGIC recrystallization mother liquor, which specifically is: 287.5g of TGIC recrystallization mother liquor is added into a four-neck flask, the temperature is raised to 70-75 ℃ (the heating temperature is within the fluctuation range), and methanol is removed under the normal pressure condition, so that 35.4g of TGIC still residue is obtained.

This example provides a method for preparing an epoxy resin from a triglycidyl isocyanurate production byproduct, comprising the steps of:

(1) To a 1.5L reactor with mechanical stirrer, thermometer, reflux condenser and dropping funnel, 35g TGIC production by-product (0.12 moL epoxy value) and 27.4g bisphenol A (0.12 moL) were added and the mixture heated to 80 deg.C and the first base was added dropwise over 15min with continuous stirring: 24g40.0wt.% NaOH solution (0.24 moL), and keeping the reaction for 2h to obtain a pre-polymerization solution;

(2) Keeping the temperature within the range of 80-85 ℃ (heating temperature fluctuation), sequentially adding 300g (1.314 moL) of bisphenol A, 168g (1.82 moL) of epichlorohydrin, 66g of water and 78g of benzene (1 moL) into the pre-polymerization solution obtained in the step (1), and dropwise adding a second batch of alkali: 173g (1.725 moL) of 40wt.% NaOH solution, and the whole reaction system is kept stirred for 3 hours at the temperature of 80-85 ℃ to carry out a ring-closing reaction to prepare epoxy resin, so as to obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product obtained in the step (2) by 117g of benzene (1.5 moL), standing for 30min, separating brine, washing the mixture by 200g of water at the temperature of 70-80 ℃, standing and separating twice, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.33KPa, and distilling off the solvent at the temperature of 190 ℃ to obtain 448g of solid epoxy resin.

Example 2

In this embodiment, the source of the by-product in triglycidyl isocyanurate production is the residue of distillation of TGIC recrystallization mother liquor, which specifically is: 287.5g of TGIC recrystallization mother liquor is added into a four-mouth flask, the temperature is raised to 70-75 ℃ (the heating temperature fluctuation range), and methanol is removed under the normal pressure condition to obtain 35.4g of TGIC distillation still residue.

(1) To a 1.5L reactor with mechanical stirrer, thermometer, reflux condenser and dropping funnel, 35g TGIC production by-product (epoxy value 0.12 moL) was added 54.8 bisphenol A (0.24 moL) and the mixture heated to 85 ℃ and the first base was added dropwise over 15min with continuous stirring: 12g of 40wt.% NaOH (0.12 moL), and keeping the reaction for 4h to obtain a pre-polymerization solution;

(2) Keeping the temperature within the range of 90-95 ℃ (heating temperature fluctuation), sequentially adding 300g (1.074 moL) of bisphenol A, 168g (1.82 moL) of epichlorohydrin, 66g of water and 92.1g of toluene (1 moL) into the pre-polymerization solution obtained in the step (1), and dropwise adding a second batch of alkali: 173g of 40wt.% NaOH solution (1.725 moL), and the whole reaction system is kept stirred for 3 hours at the temperature of 80-85 ℃ to carry out a ring-closing reaction to prepare epoxy resin, so as to obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product obtained in the step (2) by 276g of toluene (3.0 moL), standing for 30min, separating out brine, washing the standing separated mixture twice by 200g of water at the temperature of 70-80 ℃, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.33KPa, and evaporating the solvent at the temperature of 150 ℃ to obtain 432g of solid epoxy resin.

Example 3

In this embodiment, the source of the by-product in triglycidyl isocyanurate production is the residue of the distillation of TGIC recrystallization mother liquor, which specifically is: 2875g of TGIC recrystallization mother liquor is added into a four-neck flask, the temperature is raised to 70-75 ℃ (the heating temperature fluctuates), methanol is removed under the normal pressure condition, 364g of TGIC distillation kettle residue is obtained, and the epoxy value is measured to be 0.34moL/100g.

(1) To a 15L mechanical stirrer, thermometer, reflux condenser and dropping funnel reactor, 350g TGIC production by-product (1.2 moL epoxy value) 274g bisphenol A (1.2 moL) was added and the mixture heated to 80 ℃ dropping the first base over 15min with continuous stirring: 240g of 40wt.% NaOH (2.4 moL), and keeping the reaction for 4 hours to obtain a pre-polymerization solution;

(2) Keeping the temperature within the range of 80-85 ℃ (heating temperature fluctuation), adding 3000g (13.14 moL) of bisphenol A, 1680g (18.2 moL) of epichlorohydrin, 660g of water and 921g of toluene (10 moL) into the pre-polymerization solution obtained in the step (1) in sequence, and dropwise adding a second batch of alkali: 1730g (17.25 moL) of 40wt.% NaOH solution, keeping stirring the whole reaction system at the temperature of 80-85 ℃ for 3 hours, and carrying out a ring-closing reaction to prepare epoxy resin to obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product in the step (2) by 2302g of toluene (24.98 moL), standing for 30min, separating brine, washing the mixture subjected to standing separation twice by using 2kg of water at the temperature of 70-80 ℃, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.33KPa, and distilling off the solvent at the temperature of 190 ℃ to obtain 4500g of solid epoxy resin.

Example 4

In this embodiment, the source of the by-product in triglycidyl isocyanurate production is the residue of the distillation of TGIC recrystallization mother liquor, which specifically is: 2875g of TGIC recrystallization mother liquor is added into a four-neck flask, the temperature is raised to 70-75 ℃ (the heating temperature fluctuates), methanol is removed under the normal pressure condition, 380g of TGIC distillation kettle residue is obtained, and the epoxy value is measured to be 0.34moL/100g.

(1) To a 15L mechanical stirrer, thermometer, reflux condenser and dropping funnel reactor, 350g TGIC production by-product (1.2 moL epoxy value) 274g bisphenol A (1.2 moL) was added and the mixture heated to 80 ℃ dropping the first base over 15min with continuous stirring: 240g of 40wt.% NaOH (2.4 moL), and keeping the reaction for 3 hours to obtain a pre-polymerization solution;

(2) Keeping the temperature within the range of 80-85 ℃ (heating temperature fluctuation), adding 3000g (13.14 moL) of bisphenol A, 1680g (18.2 moL) of epichlorohydrin, 660g of water and 921g of benzene (11.79 moL) in sequence into the pre-polymerization solution obtained in the step (1), and dropwise adding a second batch of alkali: 1730g (17.25 moL) of 40wt.% NaOH solution, keeping stirring the whole reaction system at the temperature of 80-85 ℃ for 3 hours, and carrying out a ring-closing reaction to prepare epoxy resin to obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product in the step (2) by 1950g of benzene (24.96 moL), standing for 30min, separating brine, washing the mixture by standing and separating twice by using 3kg of water at the temperature of 70-80 ℃, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.33KPa, and distilling off the solvent at the temperature of 190 ℃ to obtain 4480g of solid epoxy resin.

Example 5

The source of the triglycidyl isocyanurate production by-product in this example was the same as that in example 1.

(1) To a 15L reactor with mechanical stirrer, thermometer, reflux condenser and dropping funnel charged with 350g TGIC production by-product (1.2 moL) 274g bisphenol A (1.2 moL) was added and the mixture heated to 85 ℃ dropping the first base over 20min with continuous stirring: 200g of 42wt.% NaOH (2.1 moL), and keeping the reaction for 2.5h to obtain a pre-polymerization solution;

(2) Keeping the temperature within the range of 85-90 ℃ (heating temperature fluctuation), adding 3000g (13.14 moL) of bisphenol A, 1680g (18.2 moL) of epichlorohydrin, 660g of water and 921g of benzene (11.8 moL) into the pre-polymerization solution obtained in the step (1) in sequence, and dropwise adding a second batch of alkali: 800g (9.97 moL) of 50wt.% NaOH solution, keeping stirring the whole reaction system at 85-90 ℃ (heating temperature fluctuation) for 1.5h, and carrying out ring-closing reaction to prepare epoxy resin to obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product obtained in the step (2) by 1950g of benzene (25 mol), standing for 25min, separating out brine, washing the mixture subjected to standing separation twice by using 4kg of water at the temperature of 75-85 ℃, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.2KPa, and evaporating the solvent at the temperature of 186 ℃ to obtain 4328g of solid epoxy resin.

Example 6

(1) To a 15L reactor with mechanical stirrer, thermometer, reflux condenser and dropping funnel, charged with 350g TGIC production by-product (1.2 moL) was added 548g bisphenol A (2.4 moL) and the mixture heated to 75 ℃ and the first base was dropped in over 12min under continuous stirring: 480g of 50wt.% NaOH (2.5 moL), and keeping the reaction for 4 hours to obtain a pre-polymerization solution;

(2) 8600g (37.67 moL) of bisphenol A, 5300g (57.3 moL) of epichlorohydrin, 660g of water and 4200g of benzene (53.8 moL) are added in sequence to the pre-polymerization solution in the step (1) with the temperature kept in the range of 85-90 ℃ (heating temperature fluctuation), and a second batch of alkali is added dropwise: 1132g (9.97 moL) of 50wt.% NaOH solution, and the whole reaction system is kept stirred for 1.5h at the temperature of 90-95 ℃ (heating temperature fluctuation) to carry out ring-closing reaction to prepare epoxy resin and obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product obtained in the step (2) by 2090g of benzene (26.79 mol), standing for 30min, separating out brine, washing the standing separated mixture twice by using 3.5kg of water at the temperature of 75-85 ℃, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.2KPa, and evaporating the solvent at the temperature of 186 ℃ to obtain 10745g of solid epoxy resin.

Example 7

This example provides a process for producing an epoxy resin from a triglycidyl isocyanurate production by-product, which is the same as in example 1 except that bisphenol A in step (2) is added as it is in step (1).

Example 8

The source of the by-product in the production of triglycidyl isocyanurate in this example was the same as that in example 1.

This example provides a method for preparing an epoxy resin from a triglycidyl isocyanurate production byproduct, which is the same as example 1 except that bisphenol a and epichlorohydrin are added in step (1) at one time, and specifically includes the following steps:

(1) To a 1.5L reactor equipped with mechanical stirrer, thermometer, reflux condenser and dropping funnel was added 35g of TGIC production by-product (0.12 moL epoxy value), 327.4g of bisphenol A (1.434 moL) and 168g (1.82 moL) of epichlorohydrin and the mixture was heated to 80 ℃ and the first base was added dropwise over 15min with continuous stirring: 24g40.0wt% NaOH solution (0.24 moL), and keeping the reaction for 2 hours to obtain a pre-polymerization solution;

(2) And (2) keeping the temperature within the range of 80-85 ℃ (heating temperature fluctuation), sequentially adding 66g of water and 78g of benzene (1 moL) into the pre-polymerization solution obtained in the step (1), and dropwise adding a second batch of alkali: 173g (1.725 moL) of 40wt.% NaOH solution, and the whole reaction system is kept stirring for 3h at the temperature of 80-85 ℃ for ring-closing reaction to prepare epoxy resin, so as to obtain a mixed product containing the epoxy resin;

(3) Diluting the mixed product obtained in the step (2) by 117g of benzene (1.5 moL), standing for 30min, separating brine, washing the mixture subjected to standing separation twice by 200g of water at the temperature of 70-80 ℃, removing residual moisture from the washed epoxy resin azeotrope, reducing the pressure to 1.33KPa, and evaporating the solvent at the temperature of 190 ℃ to obtain 448g of solid epoxy resin.

3. Test and results

The properties of the epoxy resins prepared by the above examples were tested, and the yield of the epoxy resin (the yield is the yield in terms of bisphenol a) was calculated from the mass of the obtained epoxy resin.

Epoxy value test method: according to the GB/T1677-2008 (hydrochloric acid-acetone method) standard for measuring the epoxy value of the plasticizer, sodium hydroxide standard solution is adopted to titrate an acetone hydrochloride solution in which an epoxy resin sample is dissolved, and a cresol red and thymol blue mixed indicator is used as an indicator.

The method for testing the chlorine content comprises the following steps: reference is made to GB/T12007.3-1989.

Method for testing softening point: according to the GB/T12007.6-1989 epoxy resin softening point determination method-ring and ball method standard, a softening point tester is adopted to determine the softening point of the resin.

The test results of the above examples and comparative examples are shown in table 1.

TABLE 1

From table 1, the following points can be seen:

(1) It can be seen from the comprehensive examples 1 to 8 that in the examples 1 to 8, the triglycidyl isocyanurate production byproduct, epichlorohydrin and bisphenol A are subjected to ring-opening polycondensation and then subjected to ring-closing to form the solid epoxy resin, so that the triglycidyl isocyanurate production byproduct can be recycled, the environmental pressure is relieved, the epoxy value of the prepared solid epoxy resin is more than 0.15g of epoxy group/100 g, the chlorine content is less than or equal to 0.15wt%, the softening point of the solid epoxy resin is more than or equal to 65 ℃, the yield is more than 92wt%, and the solid epoxy resin has good industrial application value;

(2) Combining example 1 with examples 7-8, it can be seen that, in example 1, a part of bisphenol a reacts with the by-product, and a part of bisphenol a and epichlorohydrin are added for reaction, compared with the case of example 7, in which all bisphenol a is added directly in the first step, and in example 8, in which bisphenol a and epichlorohydrin are added simultaneously in the first step, the solid epoxy resin obtained in example 1 has a chlorine content of 0.08wt%, a softening point of 75 ℃, and a yield of 96.5wt%, while the chlorine contents in examples 7 and 8 are 0.12wt% and 0.118wt%, respectively, and a softening point of 65 ℃ and 68 ℃, respectively, and yields of only 92.5wt% and 93.1wt%, respectively, thus showing that the present invention improves the yield and softening point of the epoxy resin and reduces the chlorine content by controlling the stepwise addition of bisphenol a and limiting the addition of epichlorohydrin in the second step.

In conclusion, the method for preparing the epoxy resin from the triglycidyl isocyanurate production byproducts can recycle the byproducts, the epoxy value of the prepared solid epoxy resin is more than 0.15g of epoxy group/100 g, the chlorine content is less than or equal to 0.15wt%, the softening point of the solid epoxy resin is more than or equal to 65 ℃, and the yield is more than 92wt%, so that the market demand is met.

The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of the raw materials of the product of the present invention, and the addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. A method for producing an epoxy resin from a triglycidyl isocyanurate production byproduct, comprising: preparing epoxy resin from triglycidyl isocyanurate production by-products, bisphenol A and epoxy chloropropane under the action of alkali;

the method comprises the following steps:

(1) Carrying out ring-opening reaction on a triglycidyl isocyanurate production byproduct and bisphenol A under the action of a first batch of alkali to obtain a pre-polymerization solution; the by-product of triglycidyl isocyanurate production is liquid phase distillation kettle residue or distillation kettle residue after methanol recrystallization of triglycidyl isocyanurate, wherein the liquid phase distillation kettle residue comprises triglycidyl isocyanurate;

2. The method of claim 1, wherein the triglycidyl isocyanurate production byproduct further comprises any one or a combination of at least two of 2, 3-substituted ring-closed epoxypropylisocyanurate, monoglycidyl isocyanurate, diglycidyl isocyanurate, or 1-chloro-2-hydroxy-propylisocyanurate.

3. The method as claimed in claim 1, wherein the byproduct of triglycidyl isocyanurate production has an epoxy value of 0.3-0.5 moL epoxy group/100 g.

4. The method of claim 1, wherein the triglycidyl isocyanurate production by-product is produced by a process comprising the steps of providing a molar ratio of epoxy value to bisphenol A of 0.01 to 0.2.

5. The process according to claim 1, wherein the molar ratio of the base to bisphenol a is from 1.7 to 4.5.

6. The method according to claim 1, wherein the molar ratio of the epoxy value of the triglycidyl isocyanurate production byproduct in the step (1) to the bisphenol A is 0.5-1.

7. The method of claim 1, wherein the ring-opening reaction is at a temperature of 75-85 ℃.

8. The method of claim 1, wherein the molar ratio of the first base to bisphenol a in step (1) is from 1.5 to 2.5.

9. The method of claim 1, wherein the first base comprises sodium hydroxide.

10. The method of claim 9, wherein the first base is a sodium hydroxide solution.

11. The method according to claim 10, wherein the sodium hydroxide solution has a mass concentration of 35 to 50wt%.

12. The method of claim 10, wherein the sodium hydroxide solution is added dropwise.

13. The method of claim 12, wherein the dropping time is 10 to 20min.

14. The process of claim 1, wherein the molar ratio of bisphenol A in step (2) to bisphenol A in step (1) is from 10 to 16.

15. The process according to claim 1, wherein the molar ratio of the sum of the aromatic hydroxyl groups contained in the prepolymer liquid and the hydroxyl groups in bisphenol A to epichlorohydrin in step (2) is 0.8 to 1.

16. The method of claim 1, wherein the molar ratio of the second base to the epichlorohydrin in step (2) is from 0.2 to 2.

17. The method of claim 1, wherein the second base comprises sodium hydroxide.

18. The method of claim 17, wherein the second base is a sodium hydroxide solution.

19. The method of claim 18, wherein the sodium hydroxide solution has a mass concentration of 35 to 50wt%.

20. The method of claim 18, wherein the sodium hydroxide solution is added dropwise.

21. The method of claim 20, wherein the dropping is performed for a period of 10 to 20min.

22. The method of claim 1, wherein a first solvent is also added to the ring closure reaction.

23. The method of claim 22, wherein the first solvent comprises water and an organic solvent.

24. The method of claim 23, wherein the organic solvent comprises any one of benzene, toluene, xylene, o-dichlorobenzene, or m-dichlorobenzene, or a combination of at least two thereof.

25. The method of claim 23, wherein the molar ratio of the organic solvent in the first solvent to the bisphenol a in step (2) is from 0.5 to 1.1.

26. The method of claim 23, wherein the ring closure reaction comprises adding bisphenol a, epichlorohydrin, water, and an organic solvent to the prepolymer solution in sequence, and adding a second base dropwise.

27. The process of claim 26, wherein the bisphenol a, epichlorohydrin, water and the organic solvent are added to the prepolymer solution sequentially at a temperature of 80 to 95 ℃, and the second base is added dropwise.

28. The method of claim 1, wherein the temperature of the ring closure reaction in step (2) is 80-95 ℃.

29. The method of claim 1, wherein the ring closure reaction is carried out for a time of 2 to 4 hours.

30. The process of claim 1, wherein the ring closure reaction is carried out under stirring conditions.

31. The method of claim 1, wherein the post-processing in step (3) comprises: and diluting the mixed product by using a second solvent, and sequentially carrying out solid-liquid separation, washing, solvent removal and cooling to obtain the solid epoxy resin.

32. The method of claim 31, wherein the second solvent comprises any one of benzene, toluene, xylene, ortho-dichlorobenzene, or meta-dichlorobenzene, or a combination of at least two thereof.

33. The method of claim 31, wherein the means for removing the solvent comprises distillation.

34. Method according to claim 1, characterized in that it comprises the following steps:

the production byproduct of the triglycidyl isocyanurate is prepared by mixing the epoxy value and the bisphenol A in a molar ratio of 0.5-1, wherein the molar ratio of sodium hydroxide to bisphenol A in the sodium hydroxide solution is 1.5-2.5;

the mol ratio of the organic solvent to the bisphenol A in the step (2) is 0.5-1.1;

35. An epoxy resin prepared by the method for preparing an epoxy resin from the by-product of triglycidyl isocyanurate production according to any one of claims 1 to 34.